SUMMARY OF THE INVENTION
The connector element described herein has particular application for connecting two components in a system which is likely to be subject to vibration.
According to the present invention there is provided a connector element for use in connecting together two components, the components having respective surfaces, which, when the components are connected together, abut one another, the connector element comprising:
(i) a shaft having a threaded end region and, remote from said end region, a radial flange, the shaft further having a passageway extending axially for at least part of its axial length;
(ii) a sleeve coaxial with and positioned around the shaft, the sleeve having an end surface proximate the threaded end region of the shaft and a radial flange remote from said end surface;
(iii) biasing means arranged between the radial flange of the shaft and the radial flange of the sleeve to urge the sleeve axially along the shaft in a direction away from the radial flange on the shaft;
(iv) an elongate member disposed for movement along the passageway in the shaft and coupled to the sleeve so as to undergo such movement in dependence upon axial movement of the sleeve, the elongate member having a region extending out of the shaft at the end thereof remote from the threaded end region of the shaft; and
(v) indicating means coupled to said region of the elongate member and responsive to movement thereof to indicate whether the shaft and the sleeve are in predetermined relative positions.
In one application such predetermined relative positions can be indicative that two components just abut.
The connector element can include a rotatable grip remote from said threaded end region of the shaft and coupled to the shaft so that rotation of said grip causes rotation of said shaft, said end region of the elongate member extending axially of the grip.
In the first embodiment, the grip includes means providing a surface having a recessed portion, for example of dished shape, and the indicating means comprises a resilient planar indicating element secured to said end region of the elongate member.
In a second embodiment, the grip includes means providing a surface having a slot, and the indication means comprises a further elongate member (indicator lever) pivotally mounted to said end region of the first-mentioned elongate member.
In both embodiments, the arrangement is such that the connector element operates as follows:
when the connector element is not in use the sleeve is urged by the biasing means in the direction away from the radial flange on the shaft, thereby causing the elongate member to adopt a first position in which part of the indicating element protrudes above the surface of the grip to indicate that the components are not correctly relatively positioned. In the first embodiment, the resilient planar indicating element sits in the recessed portion of the grip, whereby the shape of the indicator element is deformed so that its edges protrude above the grip surface. In the second embodiment, the indicator lever is pivoted so that its end protrudes from the slot. When the connector element is in use to connect together two such components, the indicating element will remain in that first position until the predetermined relative positions of the sleeve and shaft have been reached, when the sleeve causes the indicating element to move against the action of the biasing means towards the radial flange of the shaft thereby urging the elongate member towards the second position in which the indicating element lies flush against the grip surface, thereby indicating that the components are correctly relatively positioned. In the first embodiment the resilient planar indicating element is released from the recessed portion so that it lies flush against the grip surface. In the second embodiment the indicator lever lies within the slot.
Preferably the shaft is formed with a slot in which slides a bar which is secured to the sleeve to extend diametrically thereof and which is fixedly secured to the first-mentioned elongate member.
In the preferred embodiment the grip incorporates a torque limiting device for limiting the torque applied to the shaft after two components have been correctly relatively positioned, as indicated by the indicating means.
Since the connector element of the preferred embodiment of the present invention incorporates a torque limiting device, it will be referred to hereinafter as torque limited bolt.
The connector element described hereinafter can ensure that two components just abut when the connector element is done up and is resistant to vibration so that it will not inadvertently come undone while in use. Preferably, the connector element should be able to be positively locked against undoing itself under the influence of vibration. In addition, the connector element should preferably not exert a force greater than is required just to ensure that the components abut.